Mohammad Kargar - Academia.edu (original) (raw)

Papers by Mohammad Kargar

KAUMS Journal, 2017

Background: Acinetobacter baumannii is one of the highly antibiotic-resistant bacteria in the wor... more Background: Acinetobacter baumannii is one of the highly antibiotic-resistant bacteria in the world. This bacterium is a cause of endemic and epidemic nosocomial infections and despite many efforts, there is still no effective vaccine agains it. NlpD is one of the important antigenic agents that stimulate the immune system. So, the aim of this study was to examine gene cloning and expression of the nlpD gene of A. baumannii in human dermal fibroblast (HDF) cells. Materials and Methods: In this experimental study, the nlpD gene was amplified from A. baumannii genome using polymerase chain reaction (PCR). Then, the nlpD gene was cloned and sub-cloned in pTZ57R/T and pIRES2-EGFP vectors, respectively. Confirmation of gene cloning was performed by PCR, restriction endonuclease and sequencing methods. The final pIRES2-EGFP-nlpD recombinant vector was transformed into HDF cells using electroporation and the expression of target gene was evaluated by RT-PCR. Results: In this study, the 831...

Novelty in Biomedicine, 2017

Background: Integrons are mobile genetic elements able to obtain the antibiotic resistance gene c... more Background: Integrons are mobile genetic elements able to obtain the antibiotic resistance gene cassettes. The prevalence of integrons in the Enterobacteriaceae family has been varied and played an important role in the development of the drug resistant bacteria. The present study aimed to investigate the contribution of class 2 and 3 integrons in drug resistant Diarrheagenic Escherichia coli strains. M aterials and Methods: The 164 Diarrheagenic E. coli collected from feces samples of children in the Yasuj –Iran and all isolates were identified by standard biochemical tests. The antimicrobial susceptibility for 14 antibiotics, which are used conventionally was determined by disk diffusion. The presence of class 2 and 3 integrons in all isolates was investigated by PCR. R es ults: Of 164 E. coli isolates from children, 80.49% carried class 2 integron and the length of the amplicons ranged from 800 bp to 2 kb. Class 3 integrons were identified among 24 E. coli isolates. All the E.col...

International Journal of Pediatrics, 2014

Introduction: The aim of the present study was to investigate the presence and the frequency of ... more Introduction: The aim of the present study was to investigate the presence and the frequency of EAEC as etiologic agent of diarrhea in Shiraz. Enteroaggregative E. coli (EAEC) is increasingly recognized as a cause of often persistent diarrhoea in children and adults in both developing and developed countries, and have been identified as the cause of several outbreaks worldwide. Materials and Method: A total of 715 stool samples were collected from patients with diarrhea in Shiraz. Diarrheagenic E. coli were isolated by biochemical tests and culture from 715 stool samples collected from different hospitals. Diarrheagenic E. coli strains isolated from diarrheal stool samples were examined for the detection of the aggR gene by Real time PCR and PCR method. Results: In this study, a total of 101 (14.12%) diarrheagenic E. coli were isolated from 715 stool samples collected from different hospitals. Diarrheagenic E. coli were isolated much more frequently in the summer months than other ...

Journal of Medical Bacteriology, 2019

Background: Streptococcus pneumoniae is an important cause of respiratory tract infections. Due t... more Background: Streptococcus pneumoniae is an important cause of respiratory tract infections. Due to the recent incidence of antibiotic resistance to commonly used antibiotics, the use of quinolones in the treatment of S. pneumoniae has been taken into consideration. The aim of this study was to evaluate the molecular mechanisms of quinolone resistance in isolated strains. Methods: This study was carried out on 45 strains of S. pneumoniae isolates from clinical samples. Initially, using biochemical tests, S. pneumoniae strains were determined and using lytA gene specific primers, these strains were accomplished. Antibiotic resistance was assessed by Clinical & Laboratory Standards Institute (CLSI) criteria and eventually, and then adopting Polymerase Chain Reaction-Restriction Fragment Length polymorphism (PCR-RFLP) techniques were studied with Sau3A and MspI enzymes. Also, point mutations associated with antibiotic resistance was evaluated in parC and parE genes. Results: In 45 strains isolated, resistance to nalidixic acid, ciprofloxacin, ofloxacin, norfloxacin and levofloxacin was; 82.22%, 73.43%, 53.33%, 48.88%, and 42.22%, respectively. In clinical samples, 34 (75.55%) strains with mutations in the parC genes and 14 (31.11%) strains with mutations in parE gene were detected. Using statistical analysis, it was found that there was a significant relationship between mutations in the parC genes and resistance to nalidixic acid, ciprofloxacin, norfloxacin and levofloxacin. However, mutations in parE genes only showed the significant correlation with resistance to norfloxacin exclusively. On the contrary, unlike other studies, we demonstrated that a mutation in the parE gene could be involved in low-level resistance to quinolones. Conclusion: Due to the considerable resistance to quinolones, evaluation of these mutations is necessary in other parts of the country.

Medical Laboratory Journal, 2016

Background and Objective: Streptococcus pneumoniae is one of the leading causes of death among ch... more Background and Objective: Streptococcus pneumoniae is one of the leading causes of death among children worldwide. Nasopharyngeal colonization in children can spread pneumococcal infections in the community. This study aimed to evaluate the prevalence of S. pneumoniae strains isolated from healthy pharyngeal carriers less than 5

Jundishapur Journal of Microbiology, 2017

Background: Acinetobacter baumannii is a leading cause of worldwide nosocomial infections. As man... more Background: Acinetobacter baumannii is a leading cause of worldwide nosocomial infections. As many infections are caused by multidrug-resistant strains, the antibiotic-therapy of them has become greatly difficult. Objectives: The present study was aimed to evaluate the antimicrobial susceptibility of A. baumannii as well as cloning and expression of A. baumannii-smpA gene isolated from infectious patients. Methods: Sixty-seven samples were collected from different clinical infections wards especially intensive-care units (ICU). The A. baumannii was identified according to bacteriological standard method. The antibiotic resistance patterns of the isolates were analyzed by the disk diffusion method. The smpA was amplified by Polymerase chain reaction (PCR) following cloning and sub-cloning in T-vector and expression vector, respectively. Colony-PCR, double-digestion and DNA sequencing confirmed that smpA was cloned into the vectors. The expression of rSmpA in IPTG-induced E. coli-DE3 was examined by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Results: Thirty out of 67 isolates (44.78%) were positive for A. baumannii among which, more than 83% were resistance to all generation of Cephalosporins and the least resistance (10%) was observed for Colistin. The smpA-amplicon was 417 bp. Colony-PCR, double-digestion and sequencing showed that the target gene was inserted into the pTZ57RT and pET32a (+), successfully. Obtaining of a~15 KDa band in SDS-PAGE showed the recombinant pET32a/smpA was highly expressed. Conclusions: These results indicated that high resistance to antibiotics among isolates and high conserved of smpA gene at sequence level among A. baumannii strains, therefore it can be used as an antigenic target for generation vaccine against multi drug resistant (MDR) A. baumannii infections.

Genetika, 2015

The virulence factors such as shiga-like toxin (Stx) and immunogenic P39 protein in Escherichia c... more The virulence factors such as shiga-like toxin (Stx) and immunogenic P39 protein in Escherichia coli and Brucella melitensis are related to disease of digestive system in human worldwide. In the present study the stx2 and p39 genes were cloned into expression plasmid pEEF1D-FLAG (pcDNA 3.1+) as a divalent DNA vaccine candidate. The Enterohemorrhagic E. coli ATCC 3081 and smooth virulent B. melitensis strain M5 were obtained and cultured on specific media. Bacterial DNA was extracted from colonies and was used for p39 and stx2 genes amplification by PCR. The amplified products on 2% agarose gel electrophoresis were revealed 285 and 1220 bp fragments for stx2 and p39 genes, respectively. Each amplified genes were T/A cloned into pGEM-T easy vector and pGEM-T-stx2 and pGEM-T-p39 were produced. The stx2 and p39 genes were sub-cloned in linearized expression vector (pcDNA 3.1+) using HindIII, XhoI and XbaI restriction enzymes and pCDNA3-stx2-p39 was generated. This final construct was co...

Background and Aim: Enteroinvasive Escherichiacoli (EIEC) cause dysentery; however, it is less wi... more Background and Aim: Enteroinvasive Escherichiacoli (EIEC) cause dysentery; however, it is less widely reported than other etiological agents in studies of diarrhea worldwide. Despite its acknowledged status as a human pathogen, very little research has been conducted to identify individual risk factors for infection, possible reservoirs, or even infection rate. The objective of this study was to evaluate the real-time PCR as a rapid diagnostic tool for detection of four categories of EIEC in adult patients with diarrhea in Shiraz. Methods: A total of 430 stool samples were collected from patients with diarrhea in Shiraz, in 2012. Diarrheagenic E. coli (DEC) strains were isolated by standard biochemical analysis. We used Real time PCR and melt curve analysis to detect the presence of ipaH gene in EIEC. Results: 430 stool samples were tested in which 52 (12.09%) were identified as contaminated with E. coli by biochemical and microbiology tests. In the present study, EIEC were detected...

International Journal of Infectious Diseases, 2011

Journal of Aquaculture Development, 2021

Indian Journal of Virology, Mar 25, 2012

Hepatitis C virus (HCV) is a major public health problem and a leading cause of chronic liver dis... more Hepatitis C virus (HCV) is a major public health problem and a leading cause of chronic liver disease. An estimated 180 million people are infected worldwide. In this study, we developed a loop-mediated isothermal amplification (LAMP) assay for rapid detection of HCV genomic RNA and compared the sensitivity of LAMP with nested-PCR. A total of 30 blood samples from HCVinfected patients were analyzed with six primers targeting conserved sequences of the HCV 5 0 UTR within 70 min, under isothermal conditions at 62°C. Then, visualized by gel electrophoresis with ethidium bromide staining and detected by the naked-eye after adding SYBR Green I. All samples positive for HCV by nested PCR were confirmed by LAMP method. When visualized by gel electrophoresis and ethidium bromide staining, the HCV LAMP assay products appeared in a ladder pattern, with many bands of different sizes. The HCV LAMP product could also be detected by the naked-eye after adding SYBR Green I to the reaction tube and observing a color change from orange to green in positive samples. The HCV LAMP had the same sensitivity as a nested-PCR assay, the detection limit for the both systems were found to be 10 copies/mL of HCV RNA. The LAMP assay reported here is superior for rapid amplification, simple operation, and easy detection and will be useful for rapid and reliable clinical diagnosis of HCV in areas with limited resources, such as developing countries.

Multi-drug resistance and molecular pattern of erythromycin and penicillin resistance genes in

archives of razi institute, 2012

A variety of probiotic bacteria have been tested to control animal and foodborne pathogenic bacte... more A variety of probiotic bacteria have been tested to control animal and foodborne pathogenic bacteria in livestock. The mechanism of inhibition of pathogenic bacteria for several of those probiotic microorganisms is mediated by the production of bacteriocins. Colicins are probably the group of bacteriocins that have been most thoroughly characterized. Colicins are antimicrobial proteins produced by one strains of Escherichia coli to suppress the growth of other strains of E.coli. The present study indicated the preparation of colicin from colicinogenic bacteria. A total of three hundred rectal and rumen swabs isolated from health and diarrheic calves located in Fars province feces. One hundred and fifteen strains were confirmed as E.coli by biochemical test. Polymerase chain reaction was used to determine the following genes encoding colicins. Nearly 100% of isolates were contained at least one gene of colicin. The frequency of several classes of colicin was determined. As a result t...

Background & Aim: Rotavirus infection is the most common cause of dehydrating and gastroenteritis... more Background & Aim: Rotavirus infection is the most common cause of dehydrating and gastroenteritis among children worldwide.. The aim of this study was to determine the prevalence of rotavirus in children hospitalized with acute gastroenteritis in Imam Sajjad Hospital of Yasuj. Methods: This cross sectional-descriptive study was done on 184 stool samples of children younger than 7 years of age hospitalized at Imam Sajjad hospital of Yasuj in 2011 due to acute gastroenteritis. All samples were routinely analyzed for detection of rotavirus by Enzyme Immunoassay (EIA) test. Data was analyzed by SPSS version 16, Chi-square test and Fisher's exact test. Results: Of the 184 samples analyzed, 52(28.26%) were positive.The Results showed significant relationship between the seasonal distribution and virus detection (p=0/001). The highest incidence of rotavirus was seen in autumn with frequency of (48.08%) and the lowest in spring (5.77%). Conclusions: According to high prevalence of rotavirus infection, continual surveillance is necessary to provide useful data for formulating effective vaccines and perform diarrhea prevention programs.

Jundishapur Journal of Microbiology, 2020

Background: Gastric cancer has been introduced as the second cause of cancer death worldwide. Hel... more Background: Gastric cancer has been introduced as the second cause of cancer death worldwide. Helicobacter pylori infection is considered one of the main risk factors for this type of cancer, so that it has been classified as group I carcinogens. Objectives: The present research intended to examine the prevalence of cagA, cagC, virB2, vacA, and genotype distribution in H. pylori-infected biopsies and adenocarcinoma cases. Methods: Thirty-four H. pylori gastric biopsies taken from Western Iranian patients that were diagnosed as gastritis, gastric ulcers, and adenocarcinoma were used in this study. Two samples were taken from each patient. These samples were selected based on endoscopic observations and histological examinations. The presence of H. pylori was confirmed by the Rapid Urease test (RUT) and the ureC gene by the polymerase chain reaction (PCR) technique. Then, specific primers for vacA and cagPAI were used for genotyping H. pylori by PCR-typing. Results: The obtained resul...

Journal of Global Antimicrobial Resistance, 2020

A synergistic association between adhesion-related genes and multidrug resistance patterns of Sta... more A synergistic association between adhesion-related genes and multidrug resistance patterns of Staphylococcus aureus isolates from different patients and healthy individuals